### Queue a build ###
##Call the REST API for TFS that does a POST request to queue a build with the body of the request to be the build definition
$buildResponse = Invoke-RestMethod -Method POST -Credential $credential -ContentType application/json -Uri $postUri -Body $body

The powershell script is successfully launching the definition. However, I'm still not successfully:
- Passing in the specific source version I want to run against (example C12345)
- Passing in the custom variable values

Additionally:
If you know of the proper way to pass in the arguments such as the folder to map from source (to allow dynamically choosing different branches) then this would help.